parse geohashes in messages

app/src/main/java/com/bitchat/android/ui/MessageSpecialParser.kt

@@ -0,0 +1,53 @@
+package com.bitchat.android.ui
+
+import androidx.compose.ui.text.AnnotatedString
+
+/**
+ * Utilities for parsing special tokens in chat messages (geohashes, etc.).
+ */
+object MessageSpecialParser {
+    // Standalone geohash pattern like "#9q" or longer. Word boundaries enforced.
+    // Geohash alphabet is base32: 0123456789bcdefghjkmnpqrstuvwxyz
+    private val standaloneGeohashRegex = Regex("(^|[^A-Za-z0-9_#])#([0-9bcdefghjkmnpqrstuvwxyz]{2,})($|[^A-Za-z0-9_])", RegexOption.IGNORE_CASE)
+
+    data class GeohashMatch(val start: Int, val endExclusive: Int, val geohash: String)
+
+    /**
+     * Finds standalone geohashes within [text]. A match is returned only when
+     * the '#' token is not part of another word (e.g., not in '@anon#9qk2').
+     */
+    fun findStandaloneGeohashes(text: String): List<GeohashMatch> {
+        if (text.isEmpty()) return emptyList()
+        val matches = mutableListOf<GeohashMatch>()
+        var index = 0
+        while (index < text.length) {
+            val m = standaloneGeohashRegex.find(text, index) ?: break
+            // Adjust to only cover the geohash token starting at '#'
+            val fullRange = m.range
+            // Find the '#' within this match substring
+            val sub = text.substring(fullRange)
+            val hashPos = sub.indexOf('#')
+            if (hashPos >= 0) {
+                val tokenStart = fullRange.first + hashPos
+                // Consume '#' + geohash letters
+                var cursor = tokenStart + 1
+                while (cursor < text.length) {
+                    val ch = text[cursor].lowercaseChar()
+                    val isGeoChar = (ch in '0'..'9') || (ch in "bcdefghjkmnpqrstuvwxyz")
+                    if (!isGeoChar) break
+                    cursor++
+                }
+                val token = text.substring(tokenStart + 1, cursor)
+                if (token.length >= 2) {
+                    matches.add(GeohashMatch(tokenStart, cursor, token.lowercase()))
+                }
+                index = cursor
+            } else {
+                index = fullRange.last + 1
+            }
+        }
+        return matches
+    }
+}
+
+